Milli-Watt Power Harvesting from Dual Triboelectric and Piezoelectric Effects of Multifunctional Green and Robust Reduced Graphene Oxide/P(VDF-TrFE) Composite Flexible Films

Abstract

For a variety of mechanical energy harvesting as well as biomedical device applications, flexible energy devices are useful which require the development of environment-friendly and robust materials and devices. In this manuscript, we demonstrate a lead-free, facile, low-cost, sol–gel-processed reduced graphene oxide (rGO)/P­(VDF-TrFE) nanocomposite with multipurpose capability demonstration as a piezoelectric nanogenerator (PENG) and hybrid piezoelectric triboelectric nanogenerator (HPTENG) devices. The structural analysis of the materials shows that the interactions between the rGO and P­(VDF-TrFE) matrix help in breaking the centrosymmetry of rGO, resulting in a strong enhancement in the piezoelectric, ferroelectric, and triboelectric properties of composites over pristine P­(VDF-TrFE) films. In the case of PENG, the composite devices showed >22 times improvement in the piezoelectric output voltage over the pristine P­(VDF-TrFE) PENG device with the highest output voltage of 89.7 V for the 0.5 wt % rGO composite. Also, HPTENG devices based on composite films generated an average V OC of 227 V, much higher than the pristine P­(VDF-TrFE)-based devices. Maximum output power densities measured were 0.28 W/cm3 and 0.34 mW/cm3 for hybrid piezoelectric–triboelectric and piezoelectric devices, respectively. The triboelectric devices demonstrated lighting of 45 blue light-emitting diodes directly, connected in series, by harvesting mechanical energy generated by repeated finger tapping. The study highlights the promise of rGO/P­(VDF-TrFE) composites for PENG and HPTENG devices with dramatically improved electrical output.

Artificial Cutaneous Sensing of Object Slippage using Soft Robotics with Closed‐Loop Feedback Process

“…These interactions lead to a gradual increase in the nucleation rate of the polar β‐phase. [ 34–36 ]…”

“…The GO also can improve the crystallinity of P(VDF–TrFE). [ 35 ] Interactions between the fluorine groups of P(VDF–TrFE) and carbonyl functional groups of GO in PEDOT:PSS assist polymer chain rotation for the formation of the lamella crystal in the interface of both layers. [ 36 ] Figure S1, Supporting Information, shows details of the printing and fabrication processes, and Figure S2, Supporting Information, shows the characteristics of the electrode.…”

Unveiling the Role of Graphene Oxide as an Interface Interlocking Ingredient in Polyvinylidene Fluoride‐Based Multilayered Thin‐Film Capacitors for High Energy Density and Ultrafast Discharge Applications

“…The I D / I G ratio also increases to 0.86, ≈3.6 times higher than that of graphite. It suggests a decrease in the crystallinity, an increase in the isolated domains and defects in the basal plane and edges of GO [25a,26] …”

“…The improved Hummers’ method fabricated the GO nanosheets [25a,26c] . In brief, a mixture of graphite flakes (3.0 g) and KMnO 4 (18.0 g) was mixed with concentrated H 2 SO 4 /H 3 PO 4 (360:40 mL) followed by stirring at 50 °C for 12 h. After cooling the reaction to room temperature, the reaction mixture was poured in a mixture of 3 mL H 2 O 2 and 400 mL ice water.…”

Gold nanoparticle–cellulose/PDMS nanocomposite: a flexible dielectric material for harvesting mechanical energy

“…47 Thus the enhancement in the piezoelectric output voltage maybe attributed to the tunneling effect due to the presence of conducting Au NPs in the Au NP-cellulose/PDMS nanocomposite. 48 To ascertain that the voltage signals from the Au NPcellulose/PDMS nanocomposite samples are piezoelectric in nature the piezoelectric coefficient (d 33 ) of the cellulose/PDMS is measured using a d 33 meter. The d 33 value of the cellulose/ PDMS was found to be 8 pC N À1 .…”